Cooling device and method for manufacturing the same

ABSTRACT

Provided is a cooling device including opening/closing holes disposed in one side thereof and a cavity. Each of the opening/closing holes is actively opened and closed according to a temperature of an external heat source, and the cavity is connected to the outside of the cooling device through the opening/closing holes.

CROSS-REFERENCE TO RELATED APPLICATIONS

This U.S. non-provisional patent application claims priority under 35U.S.C. §119 of Korean Patent Application No. 10-2015-0130452, filed onSep. 15, 2015, the entire contents of which are hereby incorporated byreference.

BACKGROUND

The present disclosure herein relates to a cooling device, and moreparticularly, to a cooling device actively adjusting cooling efficiency.

Heat is generated in all systems including electronic devices andbiological tissues. When the heat is not released, in case of theelectronic devices, a circuit may be burnt or deteriorated to decreaseits performance, and, in case of the biological tissues, protein may bedenaturalized not to perform its function. Thus, to prevent theabove-described phenomenon, a cooling system needs to be applied toactively release the heat to the outside, thereby maintaining atemperature. Especially, when the cooling system is grafted ontoadvanced concept technologies such as IoT industry and thermoelectricgeneration using a body temperature, the cooling system optimized to theabove-described environment needs to be newly developed. The coolingsystem is desired to be set up in an environment in which variouscurvatures such as a human body or a complex electric circuit, andmanufactured in a thin film shape for integration or convenience.Manufacturing technologies of the cooling system in which the entiresystem is miniaturized to be attachable or wearable are required. Interms of the above-described features, most of the currently developedcooling system may not be applied to new technologies.

SUMMARY

The present disclosure provides a cooling device in which an inlet of acavity is actively opened/closed.

However, the above-described cooling device is described as an example.Thus, the present disclosure is not limited to the above-describedcooling device.

An embodiment of the inventive concept provides a cooling deviceincluding opening/closing holes disposed in one side thereof and acavity. Each of the opening/closing holes is actively opened and closedaccording to a temperature of an external heat source, and the cavity isconnected to the outside of the cooling device through theopening/closing holes.

In an embodiment, when viewed from a plan view, each of theopening/closing holes may have one of a circular shape and a triangularshape.

In an embodiment, when viewed from a plan view, a configuration of eachof the opening/closing holes may include a first portion extending in afirst direction, a second portion extending from one end area of thefirst portion in a second direction perpendicular to the firstdirection, and a third portion extending from the other end area of thefirst portion in a third direction that is perpendicular to the firstdirection and opposite to the second direction.

In an embodiment, when viewed from a plan view, the opening/closingholes may be spaced apart from each other, and the spaced distance maycorrespond to a half of a size of each of the opening/closing holes.

In an embodiment, the cooling device may further include atemperature-responsive polymer.

In an embodiment, the temperature-responsive polymer may includepoly(N-isopropylacrylamide).

In an embodiment, the cavity may be provided in plurality.

In an embodiment of the inventive concept, a method for manufacturing acooling device, the method includes: providing resist on a substrate;pressing the resist by a mold to form a first portion; bonding a secondportion having a plate shape to a lower portion of the first portion.Each of the first portion and the second portion includes atemperature-responsive polymer, the cooling device includesopening/closing holes disposed in one side thereof and a cavity, theopening/closing holes are actively opened and closed according to atemperature of an external heat source, and the cavity is connected tothe outside of the cooling device through the opening/closing holes.

In an embodiment, the resist may be ultraviolet (UV) resist, and theforming of the first portion may further include irradiating UV rays tothe resist to cure the resist.

In an embodiment, the resist may include poly(N-isopropylacrylamide).

BRIEF DESCRIPTION OF THE FIGURES

The accompanying drawings are included to provide a furtherunderstanding of the inventive concept, and are incorporated in andconstitute a part of this specification. The drawings illustrateexemplary embodiments of the inventive concept and, together with thedescription, serve to explain principles of the inventive concept. Inthe drawings:

FIG. 1 is a plan view of a cooling device according to an embodiment ofthe inventive concept;

FIG. 2 is a cross-sectional view of the cooling device taken along lineA1-A2 in FIG. 1 according to an embodiment of the inventive concept;

FIGS. 3 and 4 are perspective views for explaining an operation of thecooling device according to an embodiment of the inventive concept;

FIG. 5 is a plan view for explaining a mold used for a method formanufacturing the cooling device according to an embodiment of theinventive concept;

FIG. 6 is a cross-sectional view taken along line B1-B2 of FIG. 5 forexplaining the mold used for the method for manufacturing the coolingdevice according to an embodiment of the inventive concept;

FIGS. 7 and 8 are cross-sectional views taken along line B 1-B2 of FIG.5 for explaining the method for manufacturing the cooling deviceaccording to an embodiment of the inventive concept; and

FIGS. 9 and 10 are plan views of a cooling device according to anotherembodiment of the inventive concept.

DETAILED DESCRIPTION

The objects, other objectives, features, and advantages of the inventiveconcept will be understood without difficulties through preferredembodiments below related to the accompanying drawings. The presentdisclosure may, however, be embodied in different forms and should notbe construed as limited to the embodiments set forth herein. Rather,these embodiments are provided so that this disclosure will be thoroughand complete, and will fully convey the scope of the present inventionto those skilled in the art.

In this specification, it will also be understood that when anothercomponent is referred to as being ‘on’ one component, it can be directlyon the one component, or an intervening third component may also bepresent. Also, though terms like a first, a second, and a third are usedto describe various regions and layers in various embodiments of theinventive concept, the regions and the layers are not limited to theseterms. These terms are only used to distinguish one component fromanother component. Therefore, a portion referred to as a first portionin one embodiment can be referred to as a second portion in anotherembodiment. An embodiment described and exemplified herein includes acomplementary embodiment thereof. Like reference numerals refer to likeelements throughout.

FIG. 1 is a plan view of a cooling device according to an embodiment ofthe inventive concept. FIG. 2 is a cross-sectional view of the coolingdevice taken along line A1-A2 in FIG. 1 according to an embodiment ofthe inventive concept.

Referring to FIGS. 1 and 2, a storage part 100 including a cavity 110may be provided. The storage part 100 may include an opening part 120defined in an upper portion thereof. For example, the cavity 110 of thestorage part 100 may have a cylindrical shape. For example, the cavity110 of the storage part 100 may have a diameter of about 500 μm and aheight of about 200 μm. The diameter of the cavity 110 of the storagepart 100 may represent a diameter of a bottom of the cavity 110. Theheight of the cavity 110 of the storage part 100 may represent ashortest distance from the bottom of the cavity 110 to the opening part120. An embodiment of the inventive concept is not limited to the shapeof the cavity 110 of the storage part 100. An outer surface 130 of thestorage part 100 may be an area contacting a heat source. For example, abottom surface of the outer surface 130 of the storage part 100 maycontact a skin, an electronic circuit, or human organs (e.g., a heart).A position of the heat source is not limited to the bottom surface. Theposition may be determined by an object to be applied according to anembodiment of the inventive concept. The storage part 100 may have aflexible property. Accordingly, the cooling device according to anembodiment of the inventive concept may be disposed on an unevensurface. The storage part 100 may include the same material as that ofan opening/closing part that will be described later. For example, thestorage part 100 may include one selected from the group consisting ofpoly(N-isopropylacrylamide), hydroxypropylcellulose,poly(N-vinyllactam), polyvinyl methyl ether, and a combination thereof.

A refrigerant may be provided in the storage part 100. For example, therefrigerant may be provided in the storage part 100 by a method fordipping the cooling device according to an embodiment of the inventiveconcept in the refrigerant. The refrigerant may absorb heat of anexternal heat source and be evaporated. The refrigerant may cool theexternal heat source through the evaporation of the refrigerant. Forexample, the refrigerant may be water. The water may be naturallyevaporated in a general living environment (i.e., relative humidity ofabout 50%, about 25° C., and flow velocity of about 1.5 m/s). When thewater is used as the refrigerant of the cooling device according to anembodiment of the inventive concept, the water may cool heat that is twoor three times greater than a heating amount (about 10 mW/cm²) of ahuman body through the natural evaporation. An amount of water consumedby evaporation in the cooling device according to an embodiment of theinventive concept may be about 60 μL/min·cm².

The opening/closing part 200 may be provided on the storage part 100.The opening/closing part 200 may cover the opening part 120 of thestorage part 100. The opening/closing part 200 may have a plate shape.The opening/closing part 200 may have a flexible property. Accordingly,the cooling device according to an embodiment of the inventive conceptmay be disposed on an uneven surface. For example, the opening/closingpart 200 may include a temperature responsive material that absorbs orreleases the refrigerant according to a temperature. For example, theopening/closing part 200 may include one selected from the groupconsisting of poly(N-isopropylacrylamide), hydroxypropylcellulose,poly(N-vinyllactam), polyvinyl methyl ether, and a combination thereof.For another example, the opening/closing part 200 may include anelectrosensitive polymer (e.g., polypyrrole).

Opening/closing holes 210 passing through the opening/closing part 200may be provided. When viewed from a plan view, each of theopening/closing holes 210 may have a circular shape. Each of theopening/closing holes 210 may have a diameter of about 20 μm. Whenviewed from a plan view, the opening/closing holes 210 may be spacedapart from each other. For example, a spaced distance between the mostadjacent opening/closing holes 210 may correspond to a half of a radiusof each of the opening/closing holes 210. The cavity 110 of the storagepart 100 may be connected to the outside through the opening/closingholes 210. The opening/closing holes 210 may be actively closed andopened according to temperature variation. That is, the opening/closingholes 210 may be opened when the temperature increases and closed whenthe temperature decreases. Reference of temperature with respect toopening/closing of the opening/closing holes 210 may be varied accordingto a material constituting the opening/closing parts 200. For example,when the opening/closing part 200 includes poly(N-isopropylacrylamide),the refrigerant may be discharged when the temperature of theopening/closing part 200 is greater than about 32° C., and therefrigerant may be absorbed when the temperature of the opening/closingpart 200 is less than about 32° C. The opening/closing part 200 may becontracted when the refrigerant is discharged and expanded when therefrigerant is absorbed. Accordingly, the opening/closing holes 210 maybe opened when the temperature of the opening/closing parts 200 isgreater than about 32° C. and closed when the temperature of theopening/closing parts 200 is less than about 32° C. The above-describedopening/closing may represent partial opening/closing as well ascomplete opening/closing. The opening/closing part 200contracted/expanded depending on the temperature is described as anexample. In another example, the opening/closing part 200 may becontracted/expanded by other factors (e.g., electricity) instead of thetemperature.

According to the embodiment of the inventive concept, the cooling deviceincluding the opening/closing holes 210 that are opened/closed may beprovided. The opening/closing holes 210 is further opened to increasecooling efficiency when a temperature of the heat source is high, andthe opening/closing holes 210 is further closed to decrease the coolingefficiency when the temperature of the heat source is low. Theabove-described process may be actively performed according to thetemperature.

Hereinafter, operation of the cooling device according to an embodimentof the inventive concept will be described.

FIGS. 3 and 4 are perspective views illustrating the operation of thecooling device according to an embodiment of the inventive concept. Forsimplicity of description, description for contents that aresubstantially the same as those described with reference to FIGS. 1 and2 will not be provided. Although the opening/closing parts 200 includingthe poly(N-isopropylacrylamide) is described, an embodiment of theinventive concept is not limited to the material of the opening/closingparts 200. Although the opening/closing parts 200 opened/closeddepending on the temperature are described, an embodiment of theinventive concept is not limited thereto.

Referring to FIG. 3, the opening/closing holes 210 may be opened throughdischarging the refrigerant. As described above by referring to FIGS. 1and 2, the present operation may be performed when the temperature ofthe cooling device according to an embodiment of the inventive conceptis greater than about 32° C. When the opening/closing holes 210 areopened, the refrigerant in a vapor state is discharged to increase thecooling efficiency.

Hereinafter, a cooling process of the cooling device according to anembodiment of the inventive concept will be described. Although notshown, the refrigerant (e.g., water) may be provided in the storagepart. The refrigerant may receive heat from the heat source through thecooling device. The refrigerant may be evaporated to be converted intovapor (e.g., water vapor). The vapor of the refrigerant may bedischarged to the outside of the cooling device through theopening/closing holes 210.

Referring to FIG. 4, the opening/closing holes 210 may be further closedthan the opening/closing holes 210 in FIG. 3. As described above byreferring to FIGS. 1 and 2, the present operation may be performed whenthe temperature of the cooling device is less than about 32° C. When theopening/closing holes 210 is further closed than the opening/closingholes 210 in FIG. 3, the discharging of the vapor of the refrigerant maybe reduced to decrease the cooling efficiency further than that of thecase described with reference to FIG. 3.

Hereinafter, a method for manufacturing the cooling device according toan embodiment of the inventive concept will be described. Although amethod manufactured by nano-imprinting is described, an embodiment ofthe inventive concept is not limited thereto.

FIG. 5 is a plan view for explaining a mold used for the method formanufacturing the cooling device. FIG. 6 is a cross-sectional view takenalong line B1-B2 of FIG. 5 for explaining the mold used for the methodfor manufacturing the cooling device.

Referring to FIGS. 5 and 6, the nano-imprinting mold 300 may beprovided. The mold 300 may include a body part 310 and protruding parts320 disposed on the body part 310. The body part 310 may form the cavity110 of the storage part 100 of the cooling device described withreference to FIGS. 1 and 2. Although the body part 310 having acylindrical shape is illustrated, an embodiment of the inventive conceptis not limited thereto. For example, the body part 310 may have adiameter of about 500 μm and a height of about 200 μm. The protrudingpart 320 may form the opening/closing holes 210 of the cooling devicedescribed with reference to FIGS. 1 and 2. Although the protruding part320 having a cylindrical shape is illustrated, an embodiment of theinventive concept is not limited thereto. For example, each of theprotruding parts 320 may have a diameter and height of about 20 μm.

FIGS. 7 and 8 are cross-sectional views taken along line B1-B2 of FIG. 5for explaining the method for manufacturing the cooling device accordingto an embodiment of the inventive concept.

Referring to FIG. 7, a first portion 420 of the cooling device may beformed by the nano-imprinting process. The nano-imprinting process mayinclude thermal imprinting or UV-based imprinting process. Hereinafter,a process for forming the cooling device according to an embodiment ofthe inventive concept through the UV imprinting process will bedescribed. Resist may be provided on a substrate 410. For example, themanufacturing process of the resist may be a coating process. The resistmay have viscosity. For example, the resist may include atemperature-responsive material. For example, although the resist mayinclude one selected from the group consisting ofpoly(N-isopropylacrylamide), hydroxypropylcellulose,poly(N-vinyllactam), polyvinyl methyl ether, and a combination thereof,an embodiment of the inventive concept is not limited thereto.

The molds 300 described with reference to FIG. 5 may be provided on thesubstrate 410. Each of the molds 300 may have a top surface contacting atop surface of the substrate 410. The resist may be provided between themolds 300 and the substrate 410. The resist may be irradiated by UVrays. The resist may be cured to form the first portion 420 of thecooling device. The opening/closing holes 210 of the cooling devicedescribed with reference to FIGS. 1 and 2 may be formed through theprotruding parts 320 of the mold 300. The cavity 110 of the coolingdevice may be formed through the body part 310 of the mold 300. The mold300 and the substrate 410 may be cooled. The mold 300 and the substrate410 may be pressed in a direction away from the first portion 420 of thecooling device and separated from the first portion 420 of the coolingdevice.

Referring to FIG. 8, a second portion 430 of the cooling device may beprovided. The second portion 430 of the cooling device may have a plateshape. The second portion 430 of the cooling device may be bonded belowthe first portion 420 of the cooling device. The bonding may beperformed by using available bonding units such as heat or laser. Thesecond portion 430 of the cooling device may be substantially the sameas a lower portion of the storage part 110 of the cooling devicedescribed with reference to FIGS. 1 and 2. According to an example, thesecond portion 430 of the cooling device may include the sametemperature-responsive material as that of the first portion 420 of thecooling device. For example, the second portion 430 of the coolingdevice may include one selected from the group consisting ofpoly(N-isopropylacrylamide), hydroxypropylcellulose,poly(N-vinyllactam), polyvinyl methyl ether, and a combination thereof.

FIGS. 9 and 10 are plan views of a cooling device according to anotherembodiment of the inventive concept. For simplicity of description,description for contents that are substantially the same as thosedescribed with reference to FIGS. 1 to 8 will not be provided.

Referring to FIG. 9, the cooling device according to an embodiment maybe substantially the same as the cooling device described with referenceto FIGS. 1 and 2, except for shapes of the opening/closing holes 212.When viewed from a plan view, each of the opening/closing holes 212according to an embodiment may have a triangular shape. Although the sixopening/closing holes 212 according to an embodiment are illustrated asan example, an embodiment of the inventive concept is not limited to thenumber of the opening/closing holes 212. The method for manufacturingthe cooling device according to an embodiment may be substantially thesame as that of the cooling device described with reference to FIGS. 5to 8, except for the protruding part of the mold. When viewed from aplan view, each of the protruding parts of the mold according to anembodiment may have a triangular shape.

Referring to FIG. 10, the cooling device according to an embodiment maybe substantially the same as the cooling device described with referenceto FIGS. 1 and 2, except for shapes of the opening/closing holes 214.When viewed from a plan view, each of the opening/closing holes 214according to an embodiment may have a Z shape. The Z shape may representa shape similar to Z as well as the same shape as Z. For example, the Zshape may have a shape in which a middle line connecting two parallellines of Z is perpendicular to the two parallel lines. Although the nineopening/closing holes 214 according to an embodiment are illustrated asan example, an embodiment of the inventive concept is not limited to thenumber of the opening/closing holes 214. The method for manufacturingthe cooling device according to an embodiment may be substantially thesame as that of the cooling device described with reference to FIGS. 5to 8, except for the protruding part of the mold. When viewed from aplan view, each of the protruding parts of the mold according to anembodiment may have the above-described Z shape.

According to the embodiment of the inventive concept, the cooling deviceincluding the opening/closing hole that is actively opened/closed may beprovided.

However, the effects of the embodiment of the inventive concept are notlimited to the above-described contents.

Until now, preferred embodiments of the present invention are mainlydescribed. It will be understood by those skilled in the art thatvarious changes in form and details may be made therein withoutdeparting from the spirit and scope of the invention as defined by theappended claims. Therefore, the preferred embodiments should beconsidered in descriptive sense only and not for purposes of limitation.Therefore, the scope of the invention is defined not by the detaileddescription of the invention but by the appended claims, and alldifferences within the scope will be construed as being included in thepresent invention.

What is claimed is:
 1. A cooling device comprising opening/closing holesdisposed in one side thereof and a cavity, wherein each of theopening/closing holes is actively opened and closed according to atemperature of an external heat source, and the cavity is connected tothe outside of the cooling device through the opening/closing holes. 2.The cooling device of claim 1, wherein, when viewed from a plan view,each of the opening/closing holes has one of a circular shape, a Z shapeand a triangular shape.
 3. The cooling device of claim 1, wherein, whenviewed from a plan view, a configuration of each of the opening/closingholes comprises a first portion extending in a first direction, a secondportion extending from one end area of the first portion in a seconddirection perpendicular to the first direction, and a third portionextending from other end area of the first portion in a third directionthat is perpendicular to the first direction and opposite to the seconddirection.
 4. The cooling device of claim 1, wherein, when viewed from aplan view, the opening/closing holes are spaced apart from each other,and the spaced distance between the opening/closing holes corresponds toa half of a size of each of the opening/closing holes.
 5. The coolingdevice of claim 1, further comprising a temperature-responsive polymer.6. The cooling device of claim 5, wherein the temperature-responsivepolymer comprises poly(N-isopropylacrylamide).
 7. The cooling device ofclaim 1, wherein the cavity is provided in plurality.
 8. A method formanufacturing a cooling device, the method comprising: providing resiston a substrate; pressing the resist by a mold to form a first portion;bonding a second portion having a plate shape to a lower portion of thefirst portion, wherein each of the first portion and the second portioncomprises a temperature-responsive polymer, the cooling device comprisesopening/closing holes disposed in one side thereof and a cavity, theopening/closing holes are actively opened and closed according to atemperature of an external heat source, and the cavity is connected tothe outside of the cooling device through the opening/closing holes. 9.The method of claim 8, wherein the resist is ultraviolet (UV) resist,and the forming of the first portion further comprises irradiating UVrays to the resist to cure the resist.
 10. The method of claim 8,wherein the resist comprises poly(N-isopropylacrylamide).